Mark, N8MH noted:
> The 437.024 transmitter antenna configuration on AO-16 is Left Hand Circular
> polarity (LHCP). The receiving antenna on the bird is a 1/4 wave vertical
> whip.
>This whip operates against the body of the spacecraft as a "ground
plane"; however the spacecraft body is a cube 22 cm on a side (you can
see a picture at
http://128.54.16.15/amsat-new/satellites/satInfo.php?satID=11&retURL=/satellites/status.php
<http://128.54.16.15/amsat-new/satellites/satInfo.php?satID=11&retURL=/satellites/status.php>).
This is about half of the quarter-wavelength you'd like to see for a
proper ground reference, so the actual pattern undoubtedly has some
weird nulls.
> The fading is quite dramatic, which means the bird is spinning/tumbling, or
> some combination. We could never hear this before on AO-16 when it was
> transmitting its normal PSK signal, since we didn't hear the effect of fading
> on the uplink in this mode. Now we hear it, loud and clear!
>> It does take an uplink signal that is pretty close to on frequency (145.820).
> Adjusting for Doppler is helpful thing on the uplink.
>The receiver has a 15 kHz wide crystal filter with sharp skirts. So if
your NBFM xmtr is set with a ±5 kHz deviation, you may well find your
signal hitting the filter "walls". You may get better performance if you
crank the deviation back a bit.
73, Tom